They’re saying that in the same way terrorist is not always a slur but is used as a slur sometimes, Zionist can be used as a slur. I think it’s a fair take. It’s odd to specifically list Zionist as a contextual slur when you can just say no slurs.
I don’t know if I fully agree but that’s their argument as I understand it.
Edit: Idk why people are down voting me trying to explain someone’s argument.
If you do something like refer to all white people or all Germans as Nazis then yeah, in that context it’s a slur. But just referring to members of the Nazi party, definitely not. Extreme far right folks, personally no, I don’t view it as a slur there. Some people may disagree (probably the extreme far right people being called Nazis).